1. Field
The present invention relates to alloy formation, and more particularly, to double-sided bonding using transient liquid phase (TLP) bonding in power electronics.
2. Description of the Related Art
Double-sided bonding of power devices and other electrical devices allows for power module structures having improved thermal and electrical performance by attaching components to both the top and bottom sides of an electronic device. For example, double-sided bonding allows for double-sided cooling or chip-on-chip designs. Solder, either lead or lead-free, is commonly used for double-sided bonding.
Since the same solder is used as the bonding material for both the top and bottom sides, the bonding materials of the top and bottom sides have the same process and melting temperatures. Therefore, the top and bottom sides can be simultaneously bonded in the same soldering process. Because multiple devices need to be aligned and bonded, simultaneous bonding requires a complex assembly process. For instance, when placing the power device and the top and bottom components in a fixture for soldering, the top component and the power device may obscure the view of the bottom component, which complicates checking the alignment. Solder reflow may further create misalignment. Alternatively, different solders may be used for the top and bottom sides, requiring different process and melting temperatures, but allowing for a sequential bonding process. One side of the device is soldered first, then checked for alignment, and subsequently the other side is soldered.